Purine compounds have a wide variety of pharmacological activities. For example, many purine compounds are kinase inhibitors. Therefore, a number of solution and solid-phase methods for synthesizing purine compounds have been recently advanced.
Conventional methods for synthesizing purine compounds generally involve displacing a leaving group in a preformed purine ring system with a desired nucleophile or producing the purine ring system from an appropriately substituted pyrimidine ring system. However, none of the methods currently available provides synthesis of highly substituted purine compounds, e.g., purines having substituents on the 2-, 6-, 8-, and 9-positions with the ability to vary the substituent on each position.
Synthesis of purines from a pyrimidine compound often requires reduction of a nitro group that is present in the pyrimidine ring system. Unfortunately, currently known reduction methods give only partial reduction, are not consistently reproducible, or yield a product that is contaminated with undesirable inorganic salts which are difficult to remove. See J. Comb. Chem., 2000, 2, 249–253.
Therefore, there is a need for a method for synthesis of a highly substituted purine compounds. There is also a need for a method for selectively reducing a nitro substituent on a pyrimidine ring on a solid support-bound pyrimidine compound which provides a solid support-bound amino pyrimidine compound that is substantially free of inorganic salts.